Kneading pump



April 26, 1938.-

F. BURGHAUS ER KNEADING PUMP Filed Nov. 24, 1936 FIII INVENTOR 2 I 7% ATTORNE Patented Apr. 26, 1938 UNITED STATES PATENT OFFICE Application November 24, 1936, Serial No. 112,602 In Germany November 30, 1935 4 Claims.

The present invention relates to a kneading pump.

The kneading pump to which the present invention relates has the known features of closely enmeshing screw or worm rotors. Known rotary pumpshowever, are constructed with a constant pitch and a spacing between adjacent flanks of the threads on the respective rotors which is constant throughout the length of the thread.

The kneading pump according to the present invention differs from the known pumps in one of the most important features of the known apparatus inasmuch as worms or screws having a constantly changing chamber volume along the length of the thread are used.

The accompanying drawing diagrammatically illustrates the invention.

Fig. 1 is a longitudinal section and Figs. 2 and 3 are cross sections of a kneading pump according to the present invention on the lines -A-B and GD of Fig. 1.

The main screw rotor a and the secondary screw rotor b are rotatably mounted in the casing c which surrounds the rotors. As can be seen in the drawing the spaces between adjacent flanks of the thread oi the main rotor decrease from the left-hand and to the right-hand end, whereas the corresponding dimensions of the thread of the secondary rotor increase from-left to right. The material to be'knea'ded enters the passage formed by the. spaces between the thread of the main rotor at A as this passage is left open at this position. However, no material to be conveyed may reach the entrance to the passage provided by the spaces between the thread on the secondary rotor,

because the thread on this rotor is closely surrounded by the casing and' because a plate 9 is provided at the leading or left hand end of the thread. The passage on the main rotor does not open directly to the outlet D so that no material can pass to the outlet directly from the spaces on the main rotor a as the casing closely surrounds the perlpheryof the rotor and also abuts the right hand end of the rotor.

All the material which enters at A into the the thread spaces or the secondary rotor and then I to the outlet D. The crevices s-s may be varied during the working of the pump between a smallest and a desired largest size. The-pressure in the spaces of the main rotor is diminished by enlarging the crevices to any desired extent. To effect such variation the secondary rotor may be moved towards the left by, for instance, an adjusting nut h. At the outlet D theremay be mounted a perforated plate 1 or a regulating valve. By these means the kneading of the material under pressure is further promote d.

The movement of the material from the suction or inlet end seen in Fig. 2 to the outlet shown in Fig. 3 is dependent on the backlash which may be maintained at any desired small value. The flanks of the threads roll on one another so that solid particles cannot be deposited nor clog the threads. To make the procedure clearer it may be stated that at every cross-section normal to the axis, the passage volume of the rotor a plus the passage volume of the rotor b is a constant value. The passage volume of the rotor a decreases, according to the invention, pari passu with the increase of the passage volume of the rotor b. These effects are attained by the use of worms or screws having threads which provide passages which are narrow at one end of the thread relatively to the pitch and increase in cross-section towards the other end.

There may thus be treated very viscous and plastic masses, such as ceramic material orrubber masses which, by the time they leave the kneading pump will have been subjected toall the actions of a homogenizing treatment owing to the fact that they have been forced through a narrow slit by members which make rolling contact with each other. If the material contains large foreign bodies, these bodies collect in the last chamber of the rotor a on the pressure side and may be removed when desired. The kneading pump according to the invention, enables materials such as plastic materials to be given a treatment which is equivalent to passage of a material through a wide-mesh sieve having openings of about 0.5 millimeter or larger.

1 claim:

1. A kneading pump consisting of a casing and at least a right handed and a left handed worm arranged in the casingand having closely intermeshing threads, the threads of the worms being.

so formed that the width of the space between adjacent flanks of each thread progressively varies from one end to the other, the main worm to which the material to be kneaded is supplied by an inlet in the casing, having a thread which provides a passage which gradually decreases in volume from the inlet to the outlet side, the secondary worm which closely intermeshes with themain worm having a thread which provides a passage increasing in volume correspondingly towards the outlet of the casing.

2. A kneading pump consisting of a casing and at least a right handed and a left handed worm arranged in the casing and having closely intermeshing threads, the threads of the worms being so formed that the width of the space between adjacent flanks of each thread progressively varies from one end to the other, the main worm to which the material to be kneaded is supplied by an inlet in the casing, having a thread which provides a passage which gradually decreases in volume from the inlet to the outlet side, the secondary worm which closely intermeshes with the main worm having a thread which provides a passage increasing in volume correspondingly to- Wards the outlet of the casing, said casing substantially enclosing the said main worm at the outlet side and the said secondary worm near the inlet side.

3. A kneading pump consisting of a casing and at least a right handed and a left handed worm arranged in the casing and having closely intermeshing threads and means for moving the worms against each other in the axial direction, the threads of the worms being so formed that the width of the space between adjacent flanks of each thread progressively varies from one end casing, having a thread which provides a pasanaooc to the other, the main worm to which the material to be kneaded is supplied by an inlet in the casing, having a thread which provides a passage which gradually decreases in volume from the inlet to the outlet side, the secondary worm which closely intermeshes with the main worm having a thread which provides a passage increasing in volume correspondingly towards the outlet of the casing.

4. A kneading pump consisting of a casing and at least a right handed and a left handed worm arranged in the casing and having closely intermeshing threads and means for moving the worms against each other in the axial direction, the threads of the worms being so formed that the width of the space between adjacent flanks of each thread progressively varies from one end to the other, the main worm to which the material to be kneaded is supplied by an inlet in the sage which gradually decreases in volume from the inlet to the outlet side, the secondary worm which closely intermeshes with the main worm leaving a thread which provides a passage increasing in volume correspondingly towards the outlet of the casing, said casing substantially enclosing the said main worm at the outlet side and the said secondary worm near the inlet side.

FRANZ BURGHAUSER. 

